Method of and means for secret correspondence.



No. 650,7l6. Patented May 29, 1900.

c. E. GATES.

METHOD OF AND MEANS FOR SECRET CORRESPONDENCE.

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No. 650,7l6. Patented May 29, I900. C. E. GATES.

METHOD OF AND MEANS FOR SECRET CORRESPONDENCE.

(Application filed Dec. 1, 1898.) (No Model.)

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No. 650,7l6. Patenied May 29, I900.

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OARROLL E. eA'rEs, on NEW YORK, N. Y., AssIeNoR TO OF sAME PLACE.

PATENT EEIcE.

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METHOD OF-ANE) MEANS FOR sscasr ooRREsPoNoENoE.

srnorrrce'rron forming part of Letters Patent No. 650,716, dated my 29,1900. npplioatlonfiled December 1,1898. Serial No. 697,979. (No model.)

To 01/ whom it may cmicern:

Be it known that I, CARROLL EUGENE GATES, of thecity, countyjand State of. New York, have invented a new and useful Method of Secret Correspondence and Means for Carrying on the Same, of which the following is a specification.

The primary object of my invention is to enable two or more persons to carry on correspondence with absolute secrecy, notwithstanding the invention is in general public use and universal circulation.

In all cases I have a series, set, or number of combinations and also a number of cipher characters, but it is not necessary that the combinations and cipher characters be two separate series, though I prefer this form. If properly selected, the same series may perform both functions-first, that of the combinations, and, second, that of the cipher characters. The said combinations are intended to serve as a basis of correspondence by any one or a number being selected by any given correspondent to serve as suchbasis and may be single letters or numerals of uniform or different colors or symbols or characters of any description. These combinations may go with every code-book or other collection of words or phrases and be capable of being seen by the public and all users of my invention. The cipher characters may also be of many kinds and varieties and may also be capable of being seen by the public and any user. They will be capable of being combined into different groups or ciphers, each group or cipher standing for one and only one wordor phrase, as the case may be,

for each different selection of a combination as the basis of correspondence--that is, each different combination that may be selected will give a different group or cipher to stand for any given word or phrase, and also when a given combination has been selected each word or phrase will have a different group or cipher to represent it from each other said word or phrase. Various means may be adapted to bring about this result; but I will set forth in detail only one, which is shown and described in the accompanying drawings and following description. In this form of my invention I use two species of cipher characters-cipher index characters attached to each column of words or phrases and cipher reference characters used as hereinafter ex- .plained.

I prefer to have these two species of cipher characters homogeneonsthat is,

both the cipher index characters and cipher reference characters to be letters or both number s,-for example, in any given case for the sake of greater secrecy; but this is not essential.

In the accompanying drawings, Figure 1 represents one side of a device, known as a key, sliown broken near the center ofits length. Fig. 2 represents the reverse side of the same device. Fig. 3 represents the said key in place upon a collection of phrases. Fig. 4 represents the same in place upon a collection of words.

The word key is herein used to designate an instrument of mathematical precision bearing certain combinations, one or a number of which may be agreed upon between parties to serve as a basis of correspondence, and cipher reference characters, a code-book, or other collection of words or phrases.

Whereverthe word key is used herein it will have the above signification. Many varieties of combinations may be selected, and many sorts of cipher reference characters may readily'be devised; but I deem it sufficient to describe only one variety of combination and two sorts of cipher reference characters, one for use in cable and the other in telegraphic messages, and point out one form of arrange ment of the same with one or two modified forms. Other forms of arrangement will present themselves to one skilled in the art, as

well as other varieties of combinations and other sorts of cipher reference characters, all based, however, on the same principle.

One variety of combinations and a method of reference, with a class of reference characters designed for use in correspondence by cable and mail is shown on the key in Fig.1. Fig. 2 shows the same variety of combinations, but with another class of reference characters intended for use in domestic telegrams and other correspondence. The key as here shown may be made of any suitable material and is in the form of a narrow strip adapted to fit within the margin adjacent to the columns in which the collection of phrases or words is arranged, as shown in Fig. 3, or that of the columns of a vocabulary, as shown in Fig. 4.

On one margin of the key, Fig. 1, are imprinted a column of combinations a and on margin a a separate column of cipher reference-numbers. Combinations a consist of three repetitions of the letters of the English alphabet from A to Y, inclusive, each alphabet imprinted in a different colorsay red, green, and black.

a is a series of combinations of two Arabic figures from 01 to 50, inclusive, repeated progressively from O1 and retrogressively from 50, arranged in a column on the margin of the key opposite that on which are inscribed the aforesaid combinations.

On the reverse side of the key, Fig. 2, on one margin, are imprinted a column of combinations Z), precisely the same as the combinations a in Fig. 1 and arranged in precisely the same manner. A separate column b of cipher reference-letters arranged in series of combinations of two letters, preferably beginning with a vowel and chosen in some such way asshown, is placed in precisely the same position with regard to b that a in Fig. 1 is with regard to a. It is obvious that precisely the same result would be obtained if all the imprinting were done on one side of the key, there being in such case three columns abreast throughout the greater portion of the keyto wit, columns a, a, and b.

Cipher reference-numbers are used for cable-messages and cipher reference-letters for domestic telegrams, because the present rules of the cable companies permit the transmission of a group of not more than five Arabic figures at the cost of one word, but do not accept groups of letters, excepting regular words in use in some living language and consisting of not more than ten characters each, without extra charge, while the telegraph companies accept groups of not more than fifteen letters in any pronounceable combination at the cost of one word, but not more than one numeral. The collection of words and phrases may be arranged in many ways and will clearly depend on the arrangement of the key.

A convenient method for the form of key just described is that shown in Fig. 3, where the phrases C are arranged in correspondingly-symmetrical columns of fifty lines to a column, with margins adjacent to each column.

If it is desirable to print more than fifty lines of words or phrases to a column or page say ninety-nine lines or less-it is apparent that the cipher reference-numbers 0. may be extended to 99, with repetitions, as described. Oombinations a may be repeated in additional colors, and cipher referenceletters I) may be extended by using other vowels, each series of letters and numerals being lengthened correspondingly to avoid the possibility of two identical numerals or letters of reference in a and b falling more than once upon the column or page in Whatever position the key may have. At the top of each column are two rows of cipher index characters 0 and 0 The former, 0 is composed of three cipher index-numbers from 001 to 999, or as may be necessary to give each column a distinctive number progressively arranged. The latter, 0 consists of prononnceable combinations of cipher index-letters. At a corresponding fixed point with reference to each column is an asterisk or other mark 0 The operation of my invention in this form is as follows: X wishes to send Y the following message by cable: It is useless to make the effort. I'Ie finds the required sentence in the compilation of phrases and applies the key to the column in which the same occurs. Suppose the combination in a on which X and Y have agreed as the basis of correspondence is Black 0. Then placing said a combination against the asterisk c, as shown in the drawings, he looks for the cipher index-number at the top of the column, in this case 039, and also for the combination of cipher referencenumbers on a which are directly opposite the required phrase, in this case, according, toFig. 3, 19. and the 19 in the manner agreed upon, a simple manner being to make the first three numerals of the cipher group denote the column and the last two the designated word or phrase in said column. This manner would make the cipher for It is useless to make the effort 03919. On receipt of the message Y knows at once that the phrase is in column 039. After applying the key to the column with the combination Black 0 agreed upon against the asterisk 0 Y then reads the phrase opposite 19 on a. The operation for telegrams is similar, only letters in c and b, respectively, are used in place of the numerals in c and a.

An inverse modification of my invention, which involves the same fundamental principles, is to have the same or similar combinations in a and b imprinted on the margin of each column or page and the asterisk or fixed mark 0 imprinted on the key.

The operation for sending secret messages word for word is substantially the same. One position of the key on combination of Black U is shown in Fig. 4 upon a collection of words or vocabulary.

I wish to make it clear that in this form of my invention the arrangement and spacing of lines in the compilation O are made to conform precisely with the mathematically-uniform spacing of the combinations in a or b and the opposed sets of cipher reference-numbers or cipher reference-letters in a and b, respectively, on the key, so that words or phrases in said compilation will always register accurately with said references.

A convenient arrangement of the distinc- He then combines the O39 tive page or column cipher index-letters c is to use the customary lexigraphic indices, consisting of the first syllable of the last word or first syllable of the first word of the last phrase on the page or column, the words and phrases being alphabetically arranged. If this plan of distinctive lettering is adopted, the pronounceable group of letters used in certain correspondence will often consist of only five characters; but where a large number of words begin with the same prefix'as, for example, (Jon.-I add to said cipher index-letters at each page or column subsequent to the first an additional distinctive letter, as d in Cond. 0 Fig. 3, using the same additional letter but once in connection with the same syllable.

Some of the advantages of my invention are that by means thereof absolutely secret messages may be sent at the same time that it is in universal circulation, that consequently any two persons may correspond in perfect secrecy without going to the expense or trouble of drawing up a private code and, that, as each time two persons change the combination on which they base their correspondence they secure practically a new private code, in cases such as governmental matters of great importance it will no longer be necessary to submit each message to three or four distinct cipher transformations-to secure entire secrecy, as byprevious arrangement a new combination can be selected for each day, and thus baffle any attempts at solving the cipher system.

The loss of both the code and key by theft or otherwise is a matter of no great concern, because the secret combination, which may be carried in mind, is not thereby divulged. In this and other ways my invention'will save much solicitation, time, and expense, and it may be used with equal facility for sending either phrases or words in secret form.

What I claim as new is- 1. The combination with a collection of words or phrases arranged in a plurality of columns of combinations and means for providing a distinctand separate cipher for each said word or phrase for each different selection of a'combination as a basis of correspondence.

2. The combination with a collection of words or phrases arranged in a plurality of colums of combinations, cipher characters, and means for providing a distinct and separate group of said cipher characters for each said word or phrase for each different selection of a combination as a basis of correspondence.

3. The combination with a collection of words or phrases arranged in a plurality of columns of combinations, cipher reference characters, cipher index characters, and means for providing a distinct and separate group of characters combined from the said tion of a combination as a basis of correspond- 8o ence.

5. The cdmbination With a collection of words or phrases arranged in a plurality of columns of cipherindex characters affixed to each said column, a key movable with regard to each said column andhaving thereon cipher reference characters and combinations, and a distinctive mark affixed to each said column.

6. The combination with a collection of words or phrases arranged in a plurality of columns of cipher index characters affixed to each said column, a key movable with regard to each said column and having thereon cipher reference characters and combinations, 5

and means for providing a distinct and separate position of the said key with regard to each said column for every different selection of acombiuation as a basis of correspondence.

7. The combination with a collection of words or phrases arranged in a plurality of columns of cipher index characters attached to each said column, cipher reference characters movable with regard to each said column, combinations movable with regard to each said column but fixed with regard to said cipher reference characters, and means for providing a distinct and separate position of the combinations with regard to each said column for each different selection as a basis of correspondence.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CARROLL GATES.

Witnesses:

EDITH J. GRISWOLD, RAY A. WRIGHT. 

